Reclamation of unexploited sludge lagoons with the phytomeliorative systems creation for the Salix willow biomass cultivation

Peculiarities of sewage sludge using as a substrate for ”energetic” Salix willow cultivation are investigated. The possibility of phyto-meliorative short-crop-rotation system development on the basis of unexploited sludge lagoon is reported. Estimated value of average annual yield of ”energetic” willow biomass at planting density of 15.3 thousand pieces per hectare is 8.4 t/ha. It is established that the coefficients of cadmium, copper, nickel, lead, zinc and chromium biological accumulation by stem biomass of Salix aurita, Salix caprea, Salix fragilis, Salix cinerea cultivated on sewage sludge are in accordance with general phytoaccumulation functions of these crops growing on agricultural and heavy-metal-contaminated lands. A method for reclamation of unexploited sludge lagoons has been developed. The method includes Salix willow cultivation on unexploited sludge lagoons with artificial substrate in the form of stabilized sewage sludge using 25 cm willow cuttings (1 cm in diameter), that are planted at total density of 15.3 thousand pieces per ha in two-row tapes (row spacing 0.7 m, distance between bands 1.0 m) with sequential biomass harvesting every three years with subsequent replace of planting material after seven harvesting cycles.